I've used the .257 115 grain BT in a 257 weatherby , in the 3400 fps range and was not happy with its performance on a large boar I shot . That was the only game I took with it . Switched to accubonds in that caliber and have had great performance on deer .
When I started working up 270 weatherby loads , I went directly to the 140 accubond based off the 257 BT experience. I use 71 grains of 7828ssc ,f215m, at 3.280 oal , and get 3280 fps while being no where near max load in my particular rifle , long brass life , 0.4 moa 3 shot groups ...
haven't killed a darn thing with it .
I traditionally used ballistic tips in most every caliber but now I tend to move away from them in anything capable of over 3000 fps impacts .
That said , for deer only , lung shot only , I would use a ballistic tip at any speed and not fret . Just seems to really narrow your scenario down drastically though .
